Electric guitar system

ABSTRACT

An electric guitar having a plurality of strings and including circuitry for adjustably attenuating the input signals from the strings not played, circuitry for adjustably varying the attack of the output signals representing notes and chords, gain control circuitry utilizing a photoconductor, and a mechanically coupled feedback path for applying output signals back to the strings to sustain vibrations.

United States Patent Terymenko May 28, 1974 1 ELECTRIC GUITAR SYSTEM3,514,522 5/1970 Mussulman 84/l.26 x [75] In e or: u Francis Terymenko,O 3,612,741 10/1971 Marshall 84/].05

Ontario, Canada FOREIGN PATENTS OR APPLICATIONS Assignee: Invest entsFrance Toronto, Ontario, Canada Przmary ExammerR1chard B. WllkmsonFlledl 1972 Assistant ExaminerU. Weldon [21] AppL NOJ 301,372 Attorney,Agent, or Firm-Davis, Hoxie, Faithful] &

Hapgood [52] US. Cl 84/116, 84/1.l2, 84/121 [51] Int. Cl. G10h 3/00 [57]A T 58 Field of Search 84/l.04, 1.05, 1.11, 1.12, An electric gmar havmgPlurahty of Smngs and 84/1 15 L16, 1'19, 124, DIG 10, 1.26 cludingcircuitry for adjustably attenuating the input L14 L21 signals from thestrings not played, circuitry for adjustably varying the attack of theoutput signals represent- [56] References Cited ing notes and chords,gain control circuitry utilizing a UNITED STATES PATENTS photoconductor,and a mechanically coupled feedback path for applying output signalsback to the 32332133 131323 lfifi'ffijii: "31:: 221113? Strings gusts"3,463,868 8/1969 Laube 84/124 7 Claims, 8 Drawing Figures INPUT momSTRING A AUTOMATIC VOICE INPUT M DULE SELECTOR FIG-3) idrreuuArs SIGNAL5mm ti iniii s ia STEPPING B E ORF VOICE s'mmc FIVE c H gggg gg F MANUALEmma,

2' C41 it??? 252%) nan SELECTOR 51mm; 'I'QTTENUATE "SIGNAL (F164) 0 omom AIS CIRCUITRY t or STRINGS A,B.C. D ORE x w PERCUSSION ggm E r -4 FCUMTRDL FIVE H65) (H65) "ATTENUATE" SUSTAIN SIGNALS FDR PREAMPLIF'IER 'fggg'g AMI; LIMIBER 16-6 smmt AUTOMATIC vulcs I i' /ii F I INPUT i(FIG-5) SELECTOR susmm l (FIG-2) SEVERAL r-- PEDAL INDEPENDENT (FIG- 6)A's VOICE LINES PEDAL (SEE H63) I susmm OUTPUT J AMPLIFIER 10 MECHANICALLINKAGE m GUITAR EDDY (F1617) PATENTEDIAY 28 m4 SHEET 1 0F 6 2:6 uisepswzsmmautml QGEV Sam qqbiaibmve 8.

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ELECTRIC GUITAR SYSTEM The present invention is a musical instrumentcomprising a guitar body having several novel features and associatedelectronic circuitry.

Current electric guitars, and the devices for modification of theiroutput signals commonly known as fuzz boxes, .have several inherentlimitations in performance because of certain aspects of their design.While these limitations do not affect the utility of such guitars anddevices for many musical purposes, they do prevent the achievement ofdesirable musical effects.

For example, with current electric guitars it is difficult to produce asustained note, that is, a note which will not die down, except byutilizing an extremely high sound volume level. Therefore, a musicianmust play the guitar very loudly if he desires to use the sustained-noteeffect. Furthermore, because the sustained-note effect in currentelectric guitars is dependent on the total acoustical environment of theguitar, it is difficult to predict which notes will sustain themselvesin a given setting. This means that a travelling performer has noassurance that a note which will sustain itself in one concert settingwill also do so in another.

Current electric guitars severely limit the ability of the performer toplay melodies or chords without accompanying interference from thestrings not played. Sympathetic vibrations among the strings causesignals to be generated at strings other than those being played, andthese spurious signals are amplified and (when the guitar is used inconjunction with a tone modification device) modified along with thedesired sounds, producing interfering output signals and, in the lattercase, inter-modulation distortion. In fact, it is difficult just to keepconventional guitars silent, especially when they are used inconjunction with tone modification devices.

A third limitation of current electric guitars derives from the factthat the action of a guitar pick on the string makes the guitar in asense a percussive instrument. This limitation is accentuated by the useof fuzz" boxes and the like. Flowing melodies are difficult to execute,and the louder the instrument is played, the more prominent is theinitial click of sound produced by the plucking of the string. g

The present invention overcomes each of these limitations of currentelectric guitars and thereby allows a performer greater opportunity fordisplay of his ability. A sustained-note effect, reproducible in anyacoustical environment independent of the performers volume level, isachieved according to the invention by utilizing a mechanically-coupledfeedback path within the guitar of which the string is thefrequency-determining factor. The undesirable effects of sympatheticvibration are eliminated by providing performer-controlled, automaticselector circuitry to eliminate unwanted signals from the strings notplayed. The percussive feature presently inherent in electric guitars iscontrolled by other performer-controlled, automatic circuitry whichgives the melody or chord a bowed rather than struck sound.

These and other features of the invention will be more apparent from theillustrative embodiment described and illustrated in the accompanyingdrawings, in which:

FIG. 1 is a block diagram of the guitar system of the present invention,as applied to a six-string guitar;

FIG. 2 is a circuit diagram of the Automatic Input Selector stage;

FIG. 3 is a circuit diagram of the Voice Module stage;

FIG. 4 is a circuit diagram of the Mixer stage, also showing the Presetand Stepping Voice Selectors and. in schematic form, the ExpressionPedal;

FIG. 5 is a circuit diagram of the AGC and Percussion Regulator stages,also showing, in schematic form, the Volume Pedal;

FIG. 6 is a circuit diagram of the electrical portion of the SustainVibration system;

FIG. 7 is a cut-away side view of a guitar body containing themechanical portion of the Sustain Vibration system; and

FIG. 8 is a top view of the guitar body shown in FIG. 6.

Referring first to FIG. I, this Figure at its left side shows signalinputs from individual pick-ups mounted beneath each of the six guitarstrings A, B, C, D, E and F, which, in the present invention may be madeof any ferromagnetic material. The signal from a given string will behereinafter referred to as, e.g., signal A, signal B, etc. Signal Aenters the Automatic Input Selector circuitry associated with string Aand, if no ATTENU- ATE or blocking signal also enters that AutomaticInput Selector circuit, signal A in amplified form is applied to theinput of the Voice Module circuitry associated with string A. In theVoice Module, the signal from string A is processed to produce, in thisillustrative embodiment, six voices or electronically modified andamplified versions of the original signal. These voices are identifiedherein by one of the subscripts u-z following the letter of the stringfrom which the signal is derived, as for example, Au, Av, Aw, Ax, Ay,and A2. At the Mixer all of the like voices from the several strings arecombined into a single voice, e.g., Au, Bu, Cu, Du, Eu, and Fu arecombined into a single voice hereinafter referred to as voice U.Similarly, all the individual v voices are combined to produce voice V,etc.

Referring now in detail to FIG. 2, the circuitry of which it should beunderstood is repeated for each string, signal A from the magneticpick-up mounted in the guitar body beneath string A is applied to thebase of transistor 01 across the parallel arrangement of potentiometerR1, used to balance the amplitudes of the incoming signals from thevarious strings, and Cl, which shunts any radio frequency noise toground, and through coupling capacitor C2. Signal A is also applied tothe base of transistor Q3 through coupling capacitor C3.

The function of the Automatic Input Selector (AIS) circuitry shown inFIG. 2 is to provide the performer with the means to attenuate orcompletely block all signals from the strings not being played at agiven time, thereby eliminating unwanted sounds from the melody beingplayed.

Transistor Q1 amplifies the signal, which then passes through capacitorC4 to diode D1. Potentiometer R2 is adjusted to allow only a short burstof negative-going signal to pass diode D1, which in this illustrativeembodiment may have a threshold voltage of about 0.3 volts. The spike ofsignal passed through diode D1 passes through coupling capacitor C5 totransistor Q2,

which is biased into saturation when no signal is applied. Theapplication of the pulse to the base of Q2 results in a strongpositive-going burst of signal at the collector. This pulse is appliedacross diodes DUN-04 to the *A'l'lENUATE" inputs of the AIS circuitry ofthe other strings, not shown. For example, if the AIS circuitry forstring A is being discussed, then diodes D100-04 would be connected tothe ATTENUATE circuitry associated with strings B, C, D, E and F.

Direct coupled transistors Q3 and Q4 and their associated resistorscomprise a flat response circuit capable of amplifying or attenuatingthe signal applied at the base of Q3 depending on the bias conditions.The bias conditions in turn are dependent on the state of transistor Q8,connected between the positive source and the collectors of Q3 and Q4.The AIS control is exerted at this point, by causing Q8 to vary betweencut-off (in which case the supply voltage to Q3 and O4 is low and theoutput at the collector of O4 is attenuated) and saturation (in whichcase the supply voltage to Q3 and O4 is relatively high and the 03-04combination functions as an amplifier).

The AIS circuitry attenuates a signal in the following way. If string Bonly is struck, in the manner described above a positive signal pulseappears at the ATTENU- ATE" input of the AIS circuitry of string A andis applied to the base of transistor Q5, through potentiometer R3, whichfunctions as a sensitivity adjustment. Transistors Q5 and Q6 arearranged in flip-flop fashion, so that the ATTENUATE pulse justdescribed puts 05 into saturation and Q6 into cut-off. Had string A beenplucked, Q6 would have been put into saturation by the application ofthe positive burst to the base of 06 through diode D2. With O6 incut-off, its high collector voltage is applied to the base of transistor07 across photoconductor PHI, a variable resistor located in the AISpedal, operation of which is controlled by the performer.

The AIS Pedal, and other performer-controlled pedals discussed below,allinclude a neon bulb and one or more photoconductors. Depression ofthe pedal by the performer varies the exposure of the photoconductor tothe neon bulb NEl and hence the characteristics of the circuit of whichit is an element. In the present case, if PHI is at its lowestresistance value (pedal fully depressed), the voltage applied to thebase 07 puts that transistor into saturation. This in turn lowers thecollector voltage of Q7, which lowers the base voltage of transistor 08,biasing 08 out of saturation and sharply reducing the supply voltage totransistors Q3 and 04. In this way, the application of an ATTENUATEsignal to the AIS circuitry of a given string, given the depression bythe performer of the AIS Pedal, causes the output from transistor O4 tobe attenuated.

The performer can vary the application of this function by depressingthe AIS Pedal to less than its full extent, thereby leavingphotoconductor PHI with a substantial resistance value. If the pedal isnot depressed at all, the resistance of PHI may be made sufficientlyhigh so that no attenuation occurs, in spite of the presence of a signalat the ATTENUATE input. The choice is left to the performer.

Depending on the presence or absence of an AT- TENUATE" signal and theextent to which the Pedal is depressed, a signal of a predeterminedstrength appears at the collector of Q4. This signal is the input to theVoice Module illustrated in FIG. 3.

The function of the Voice Module of string A, the circuitry of which isrepeated for each other string of the guitar, is toprocesselectronically the amplified signal from the collector oftransistor 04, modifying or amplifying that signal to produce, in thisembodiment, six voices from signal A.

Through the parallel combination of capacitor C7 and capacitorC8-resistor R4, signal A is applied to the base of transistor Q9.Capacitor C7 has a small value which serves to boost the high frequencyresponse of the circuit to compensate for any losses and to provideclear high notes. The output of Q9, denominated voice Az, is the naturalsound of guitar string A.

Through capacitor C9 signal A is applied to the base of transistor Q10,which amplifies it and applies it both to the primary of transformer T1,and, through capacitor C10, across the parallel combination of reverseddiodes D4 and D5. The parallel arrangement of diodes D4 and D5 acts as alimiterin reverse, blocking the middle strength values of the signal andpassing the positive and negative peaks intact. The output from theparallel arrangement of diodes D4 and D5, signal A with the middlevalues removed, becomes voice Av.

Through C8 signal A is also applied to the base of Q1]. The collector ofO1] is shunted to ground through a large capacitor C11 leaving aresidual sawtooth signal which is coupled to the bases of transistorsQ12 and Q13. The amplified sawtooth signal at the collector of Q12becomes voice Aw and is also applied, together with the input to Q12,through capacitor C12 to the secondary of T1 where it mixes with theother current in the secondary to produce voice Au. The collector of Q13is coupled through capacitor C13 to the limiter composed of diodes D6and D7. The resulting signal, a near square wave, is the basis for theother three voices.

Through trimmer resistor R5, transistor 014 receives a portion of thesignal from the limiter composed of D6 and D7 and projects an amplifiedimage of the signal out of phase with the original (because of thenature of a common-emitter transistor amplifier) into the junction ofdiodes D8 and D9 through D9. The same signal with the original phasecomes to that junction directly from the limiter through D8. Diodes D8and D9 act as a full wave rectifier, and the signal at their junction israised one octave. The symmetry of the new signal appearing at thejunction of D8 and D9 is controlled by potentiometer RS. This new signalis applied to the base of transistor Q15 through the parallelcombination of capacitor C14 and resistor R6, which boosts the highfrequency components of the signal. The output of Q15 at its collectoris voice Ay and also comprises one possible input to transistor Q16.

Transistor Q16 obtains its input from the collector of either 014 orQ15, depending on the setting of manual switch S1. That is, its input iseither the square wave signal from the collector of Q14 or the signalfrom the collector of Q15, with a very strong second harmonic. Switchessimilar to S1 are provided in each Voice Module; they allow theperformer to choose between two X voices for each string independentlyof the X voices chosen for the other strings. The output at thecollector of Q16 is voice Ax.

It should be understood that all of the preceding circuitry is repeatedfor each string, so that, in the present six-string illustrativeembodiment, the circuitry shown in FIGS. 2 and 3 is repeated six times.The circuits that follow, on the other hand, are constructed only once.

As is illustrated in FIG. 4, the Mixer comprises six separate amplifiercircuits, one for each set of similar voices from the six strings. Forclarity, only two are illustrated: the circuit carrying the summation ofall the u voices, designated U, and the circuit carrying the summationof all the w voices, designated W. It should be understood that theremaining circuits are identical in design to that for these voices.

The u signals Au, Bu, Cu, Du, Eu, and Fu are all combined and appliedthrough capacitor C16 to the base of transistor Q18. Variable resistorsR8 and R9, together with capacitors C17 and C 18, control the frequencyresponse of the circuit and hence the tone of the U voice. The amplifiedoutput of Q18, voice U, is applied to both the Preset Voice Selector andthe Stepping Voice selector. The other Mixer circuits operate similarly.The amplified sawtooth voice W is also used as an input signal to thePercussion Regulator, discussed below. One of the Mixer output signalsmay also be chosen to drive the Sustain Vibration Amplifier, alsodiscussed below.

The Preset Voice Selector is simply a switch wired to select as itsoutput any one of the six incoming voices, or various combinations ofthose voices. In the illustrative embodiment, the switch is wired toselect any one of U, V, W, X, Y, Z, UY, UZ, VW, VX, WX or WY. Theseparticular outputs are entirely a matter of choice; the ear of theperformer being the ultimate decision-maker. Any other outputs could beselected. The output is made available as one input to the ExpressionPedal, discussed below.

The Stepping Voice Selector is a stepping relay whose action iscontrolled by a microswitch actuated by a backward swing of theExpression Pedal. In this illustrative embodiment, the Stepping VoiceSelector repeats its cycle every six steps and applies one of the inputvoices U, V, W, X, Y or Z as a second input to the Expression Pedal.

Footswitch S2 makes available the natural sound of the guitar, voice Z,as a third input to the Expression Pedal, replacing the second inputfrom the Stepping Voice Selector.

The Expression Pedal carries neon bulb NE2 and is designed so that, whenthe pedal is depressed, NE2 first illuminates only PH3, and then onlyPH2. The output from the pedal therefore varies from the Stepping VoiceSelector signal to the Preset Voice Selector signal as the amount ofpedal depression is increased.

The output signal from the Expression Pedal is further processed by theAutomatic Gain Control (AGC) circuit and the Percussion Regulatorcircuit (both shown in FIG. 5) before becoming the ultimate outputsignal. The signal is applied to the base of transistor 020 throughpotentiometer R11 and capacitor C20. Potentiometer R11 should beadjusted to keep the maximum incoming signal below a level which wouldcause distortion in the second stage transistor, Q21. Throughconventional amplifier circuitry the signal becomes available at thecollector 021 for the Volume Pedal and the ultimate output.

Photoconductor PH4 is connected between the collectors of Q20 and Q21,and the bias values to those transistors are adjusted so that theircollector voltages are equal and no DC. current flows through PH4: Sincethe signal at the collector of 021 is 180 out of phase with the signalat the collector of 020, because of the nature of a common-emittertransistor amplifier, if PH4 has relatively low resistance value, theoutput from 021 will be attenuated because of negative feedback from thecollector of Q21, through PH4, to the base of 021. On the other hand, ifPH4 has a relatively high resistance value, little negative feedbackwill occur and the output from Q21 will not be attenuated.

The resistance level of PH4 is controlled by neon bulb NE3, located inthe collector circuit of pnp-type transistor Q22. A portion of theoutput signal at the collector of Q21 is applied to the base oftransistor Q23 through potentiometer R12, the manually-set AGC levelcontrol. Transistor Q23 amplifies the signal and passes it to therectifier circuit composed of diode D11 and capacitor C21. The signalhere is converted to a negative D.C. value indicative of the amplitudeof the output signal at the collector of Q23. This negative voltage isthen applied to the base of transistor Q22. The negative bias causes 022to conduct, sending current through NE3, thereby reducing the resistanceof PH4 and, ultimately, attenuating the signal to the Volume Pedal in anamount dependent on the effective resistance value of R12. Therefore,the signal level at the Volume Pedal is regulated by the value of R12.

Potentiometer R12 controls the ratio of the volume of single notes tothe volume of chords. Potentiometer R12 should be adjusted so thatsingle notes do not cause NE3 to light and thus do not cause anyattenuation of the output signal but that chords, having a much higherRMS value than single notes, make NE3 glow sufficiently to attenuate theoutput signal to the strength of the single note output signal.

The Percussion Regulator (FIG. 5) takes as its input the sawtooth voiceW from the Mixer. Its function is to remove the sharp click heard whenthe guitar pick strikes the strings, thereby making melodies sound bowedrather than struck. It operates by causing each note to be eased intoaudibility, reaching its full volume about one/half second after thenote has been struck.

When the Percussion Regulator is not in operation (i.e., if switch S3 isin its open position), very little current flows through NE3 because ofthe relatively high resistance in series with NE3. Therefore, in thiscondition the resistance value of PH4 is relatively high and noattenuation occurs. Closing S3, however, puts Q24 into saturationbecause of the relatively low resistance path thereby establishedbetween B- and its base, and this makes NE3 glow brightly. The glow ofNE3 attenuates the output at the Volume Pedal by about percent in themanner described above. When any string is plucked, the W voice derivedfrom that string in the Mixer is applied to the base of transistor Q25and amplified by Q25 and Q26. The interstage coupling capacitor C22 ismade relatively small to accentuate the high frequency components of thesignal. This is done in order to compensate voice W for its relativeweakness in high frequency components which results from the manner inwhich voice W was generated, i.e., the presence of capacitor Cll betweenthe collector and the base of transistor 011.

The output signal from Q26 is rectified by diode D12 into a positive DC.signal proportional to the strength of the W signal applied. CapacitorC23, of relatively large value, smoothes this signal. This positivesignal serves to lower the degree of negative bias at the base ofpnp-type transistor Q24, tending to turn this transistor off and therebydim NE3. Photoconductor PH4 is a comparatively low speed photoconductor,for example a NSL-457, whose frequency response drops off sharply belowabout 60 Hz, and because of its slow recovery rate and the time delay inthe circuit controlling NE3 caused by capacitor C23, the output signalat the collector of 021 rises gradually in strength from a low leveldetermined by the maximum attenuation available by the action of PH4 toits normal unattenuated level, with the initial percussive attackeliminated from the note. The maximum attenuation is that produced bythe lowest attainable resistance value of PH4. Potentiometer R13, at theinput to the Percussion Regulator, controls the audible duration of thenote and the overall sensitivity of the system.

Capacitor C22, by boosting the deficient high frequency component ofvoice W, ensures that the Percussion Regulator will operate in the samemanner for high and low notes. If the high frequency components were notboosted, voice W for a low note would be a stronger signal than voice Wfor a high note, and this would cause a low note to rise into audibilitymore rapidly, last longer, and decay from audibility more rapidly thanhigh note. This would be an undesirable musical characteristic.

The Volume Pedal (FIG. 5) is a neonphotoconductor combination asdescribed above which allows the performer to vary the volume of theoutput signal.

The circuitry just described possesses an additional advantage. Oneconventional tone modification device in wide use, known as a wah-wahpedal, comprises a passive electrical circuit in series with the outputsignal of the guitar and including as one element thereof a variableresistance element under the control of the performer. Depending on theinstantaneous setting of the resistance, a matter determined by theperformer, this device primarily passes only low or high frequencies. Inoperation, performers attempt to synchronize their depression of thepedal with the playing of the notes, to give each note a similarfrequency profile, but this is quite difficult to accomplish.

The present system provides means for obtaining the wah-wah effectautomatically without relying on the performer's skill. Neon bulb NE3 isilluminated each time a note is struck, and this causes the resistanceof photoconductor PH4 to drop each time in the manner described above.If a photoconductor similar to PH4 were placed in series with the outputsignal and exposed to NE3, the wah-wah" effect could be achievedautomatically.

If the performer desires, a note played on this guitar can be sustainedfor any desired length of time, at any volume level, in any acousticenvironment. This is accomplished, as indicated generally in FIG. 1, byamplifying and shaping one of the voices from the string being playedand converting the processed signal into a mechanical vibration conveyedback to the string. In the illustrative embodiment shown, the inputsignal for the Sustain Vibration system is chosen to be the X signalfrom the Mixer, but another voice could be used if desired.

The Sustain Vibration circuit, shown in detail in FIG. 6, includes a twostage transistor preamplifier of standard design, a limiter made up ofdiodes D and D16, the Sustain Pedal, transformer T2, switch S5, and aplayed.

When the Sustain function is activated, the amplified signal from thepower amplifier is converted into a mechanical vibration conveyed backto the guitar string by apparatus shown in FIGS. 7 and 8. The apparatus,shown in relation to guitar body 50, includes a permanent magnet 51mounted in the guitar and a coil 52 in movable relationship to themagnet and rigidly attached to the underside of extension 53 of guitarbridge 54. FIG. 7 shows this relationship between the coil and extensionschematically. The coil, which conveniently may be several turns ofcopper wire on a form, receives its signal from the power amplifier. Itis free to move with respect to the magnet as much as the flexibility ofthe extension will allow. Bridge 54, including its extension 53, iscommonly made of steel and is securely held in place by supporting posts55. Strings 56 extend from tailpiece 57, across the bridge 54, overpickups 58, and on to the neck of the guitar.

In operation the presence of a signal in coil 52 causes it to vibratevertically with respect to magnet 51, rigidly mounted in body 50. Thesevibrations are transmitted to that part of the bridge in contact withthe strings by its extension 53, thereby completing a feedback path ofwhich theguitar string is the frequency determining factor. Operation ofthis system is totally independent of the output volume level of theguitar and the acoustics of the concert setting.

The coil-magnet combination can be mounted anywhere on the guitarprovided only that it is not in the inductive range of the pickups.Furthermore, the coil could transmit its vibrational energy to thestrings through a connection other than the bridge extension heredisclosed. The system should be designed so that there is no dominantresonant frequency in the coilstring coupling within the frequency rangeof the strings. In addition, correct phase alignment between the signalat the coil and the signal at the pick-ups should be maintained. Correctalignment is obtained by use of switch S5 and transformer T2. The centertap of the transformers secondary winding is common and the two extremesare both available, by activation of S5, as alternate sources for thecoil driving signal.

With the sustain vibration system in operation, the performer can playwith his left hand only, the minute response found naturally in eachstring, when fed back to the bridge by the mechanical feedback systemhere disclosed, being sufficient to sustain the note. This can be donewithout affecting the quality or volume of the ultimate guitar output.

The following are the values of the circuit components used in theillustrative embodiment of my invention previously discussed:

A. Components discussed RI 470 ohms D1 D100-04 All other diodes C16 C17C18 C20 C21 C22 C23 10K ohms 1K ohms 120K ohms 470K ohms 24K ohms 500Kohms 500 K ohms 47K ohms 500K ohms 100K ohms 300 ml 30v 6.4 mf 30v 10 ml30v 25 mf v 25 ml" 30v 0.22 ml' 70v 033 ml' 70v 0.1 ml" 70v 0.22 ml 70v0.3

680 pf 70v 0.001 ml 70v 0.0015 mf 70v 0.002 ml 70v 0.005 ml 70v 0.03 ml70v 0.05 ml 70v 0068 ml' 70v 0.01 ml 70v 0.02 ml 70v 0.02 ml 70v 0.033ml 70v 0.05 ml" 70v 0.05 inf 70v 0.1 ml' 70v 0.133 mf70v 0.168 ml 70v 2Smf'70v 50 ml 70v 100 ml 70v 0.01 ml 70v 0.0[5 ml" 70v 0.02 mf 70v 0.03ml 70v 0.033 ml 70v 0.05 ml" 70v 0.168 ml" 70v 0.2 ml" 70v 0.22 mf 70v0.1 ml 70v 0.02 ml 30v 0.25 ml" 30v 0.03 ml 30v 6.4 ml 25v 0.005 ml' 70v0.01 mf 70v (Phillips EO97AC Polcnliomclcr) (Phillips EO97ACPotcriliomctcr) (Phillips EO97AC Polcnliomclcr) O18 O20 O21 O22 O23 O24O25 O27 Q28 2N3415 2N3415 2N3415 2N3415 B. Components not specificallydiscussed 100K ohms 3K ohms 33K ohms no resistor 22K ohms 2.2M ohms 39Kohms 510 ohms 100K ohms 13K ohms 82K ohms K ohms K ohms 18K ohms ohms120K ohms 0.1 ml 70v 20 ml 25v 3 mf 25v 610 ohms 0.02 ml 30v 30K ohms68K ohms 8.2K ohms 3.6K ohms 36K ohms 1 1K ohms 680K ohms 15K ohms 4.3Kohms 100 ohms 120K ohms 5.6K ohms 68K ohms 470K ohms 51K ohms 20K ohms9.1K ohms 56K ohms l.6 mf 70v 2.5 ml 70v 6.4 ml" 70v 100K ohms 3.3K ohms62K ohms 100K ohms 6.8K ohms 1 10K ohms 1.6 ml 70v 2.5 mf 70v 6.4 mf 70v15K ohms 2K ohms K ohms 130K ohms 360K ohms 0.02 mf 70v 0.03 ml70v0.04mf 70v 0.05 ml 70v 0.07 mf 70v 4.7K ohms 100K ohms 68K ohms 1.3Mohms 82K ohms 100K ohms 3K ohms 43K ohms 270K ohms 47K ohms 1.2M ohms910K ohms 1M ohms 1K ohms 91K ohms 75K ohms 2K ohms K ohms (PhillipsEO97AC Potcmiomctcr) I92 I93 I94 I95 I96 I97 I98 I99 200 20I 202 2I6 2I72I8 219 220 ZZI 222 223 16K ohms 12K ohms 6.4mf 25v 20K ohms 6.4 mt 25v62K ohms 47K ohms )IK ohms lK ohms I l0K ohms 39K ohms 43K ohms 8.2Kohms 6.4 mf 25v 33K ohms 56K ohms 2.7K ohms 0.22 mi 70v 43K ohms 56Kohms 3K ohms 33K ohms 0.22 ml 70v 470K ohms 56K ohms 3K ohms 33K ohms6.4 ml" 25v 62K ohms K ohms 6.4 ml v I600 ml 64v Miscellaneous R8/R9 isan ohmite dual CCU-5041.

All neons are AIA. All photoconductors are Phillips B8-73l-05 exceptPH4, which is an NSL-457.

(Phillips E097AC Potcntiomctcr) (Phillips EO97AC Potcntiomctcr)potentiometer No.

The transformers TI and T2 are both Armaco At-46.

I claim: I. An electronic plural-stringed musical instrument having:

means associated with each of the strings independently for producing anelectrical signal derived from the vibration of that string, and meansfor selecting only the electrical signal having an amplitude above athreshold level and for attenuating electrical signals derived from theremaining strings. 2. The instrument of claim I wherein the means forselecting includes means for producing control signals for effecting theattenuation of the signals derived from each of the remaining strings.3. The instrument of claim 2 wherein the degree of attenuation isadjustable.

4. An electronic musical instrument having: a plurality of stringspassing over a supporting bridge,

means associated with each of the strings independently for producing anelectrical signal derived from the vibration of that string, means forselecting only the electrical signal having an amplitude above athreshold level and for attenuating electrical signals derived from theremaining srings, voicing means for processing the said selectedelectrical signal, a mixing device coupled to the voicing means forreceiving the said processed selected electrical signal, and meansconnected to the said mixing device for producing a vibratory motionrelated to the selected signal and applying the motion directly to thebridge only to sustain the vibration of the string originating theselected signal. 5. The instrument of claim 4 wherein the motionproducing means includes an electromagnetic coil and core assembly and asubstantially rigid connection between the assembly and the bridge.

6. An electronic plural-stringed musical instrument having:

pick-up means associated with each of the strings independently forproducingan electrical signal derived from the vibration of the string,

independent amplifier means associated with each of the pick-up meansfor amplifying the signal from that pick-up means,

means for selecting only an amplified electrical signal from one of theamplifier means having an amplitude above a threshold level and forproducing from said amplified signal control signals for effecting theattenuation of the signals derived from each of the remaining strings.

7. The instrument of claim 6 wherein the means for selecting includesdiode means having a threshold voltage at the threshold level.

1. An electronic plural-stringed musical instrument having: meansassociated with each of the strings independently for producing anelectrical signal derived from the vibration of that string, and meansfor selecting only the electrical signal having an amplitude above athreshold level and for attenuating electrical signals derived from theremaining strings.
 2. The instrument of claim 1 wherein the means forselecting includes means for producing control signals for effecting theattenuation of the signals derived from each of the remaining strings.3. The instrument of claim 2 wherein the degree of attenuation isadjustable.
 4. An electronic musical instrument having: a plurality ofstrings passing over a supporting bridge, means associated with each ofthe strings independently for producing an electrical signal derivedfrom the vibration of that string, means for selecting only theelectrical signal having an amplitude above a threshold level and forattenuating electrical signals derived from the remaining srings,voicing means for processing the said selected electrical signal, amixing device coupled to the voicing means for receiving the saidprocessed selected electrical signal, and means connected to the saidmixing device for producing a vibratory motion related to the selectedsignal and applying the motion directly to the bridge only to sustainthe vibration of the string originating the selected signal.
 5. Theinstrument of claim 4 wherein the motion producing means includes anelectromagnetic coil and core assembly and a substantially rigidconnection between the assembly and the bridge.
 6. An electronicplural-stringed musical instrument having: pick-up means associated witheach of the strings independently for producing an electrical signalderived from the vibration of the string, independent amplifier meansassociated with each of the pick-up means for amplifying the signal fromthat pick-up means, means for selecting only an amplified electricalsignal from one of the amplifier means having an amplitude above athreshold level and for producing from said amplified signal controlsignals for effecting the attenuation of the signals derived from eachof the remaining strings.
 7. The instrument of claim 6 wherein the meansfor selecting includes diode means having a threshold voltage at thethreshold level.